In January, the Internal Revenue Service clarified its definition of "service charge" - to include those automatic gratuities. That means these kinds of tips are now treated as regular wages, subject to payroll tax withholding - instead of standard tips, which restaurants leave up to the employees to report as income.
So accordingly, service charges must be included in the calculation of hourly employees' regular rate of pay which could affect overtime calculations. That also means hourly pay rates could vary day to day depending on how many large parties are served. The IRS ruling on automatic gratuities was actually issued in June 2013. However the agency delayed implementation until January 2014 to give restaurants and other affected businesses time to comply.
The IRS established the following rules that make a payment a tip:
Therefore, according to the updated rule, automatically added tips are service charges because they aren't voluntary. In a question-and-answer section of the ruling, the IRS provided an example of a restaurant suggesting different tip amounts, and said that practice isn't subject to federal withholding because the customer is still free to choose whether and how much to tip.